The Siemens SM 1231 PLC analogue I/O module has 8 integrated input with a signal range of (0)4 to 20mA. It is designed for use with SIMATIC S7-1200 PLCs. It is optically isolated and has 8 analogue inputs. It supports input in the form of voltage or current. It has advanced features like alarms and diagnostics that make it an ideal choice for analogue heat-sensing applications.
SIMATIC S7-1200, Analogue input, SM 1231, 8 analogue inputs, +/- 10 V; +/- 5 V; +/- 2.5 V; 0-20 mA/4-20 mA, 12 bits + sign bit (13 bits ADC)